Volume 86, Issue 1, July (2001), pp. 13-19 © The Author 2001

Medline/PubMed Citation | Related Articles in PubMed | Download to Citation Matcher  

Effects of dietary coconut oil on apolipoprotein B synthesis and VLDL secretion by calf liver slices

Dominique Gruffat-Mouty¹*, Benoît Graulet¹, Denys Durand¹, Marie Elisabeth Samson-Bouma² and Dominique Bauchart^1
1Unité de Recherches sur les Herbivores, Équipe Nutriments et Métabolismes, Institut National de Recherche Agronomique, Centre de Recherches Clermont Ferrand - Theix, 63122 Saint Genès Champanelle, France
²INSERM U 327, Faculté de Médecine Xavier Bichat, 16 rue Henri Huchard, BP 416, 75870 Paris Cedex 18, France

 (Received 31 March 2000–Revised 18 January 2001–Accepted 25 January 2001)

Incorporation of coconut oil (CO) rich in lauric acid into the milk diet induces a lipid infiltration of the liver (steatosis) in 1-month-old calves. Among possible steps involved in diet-induced liver steatosis, the ability of the calf liver to synthesize apolipoprotein (Apo) B and to secrete it as part of VLDL particles was investigated. Liver samples were taken from calves fed for 17 d on a conventional milk replacer containing CO (n 5) and beef tallow (BT, n 4) as reference. Samples were cut into slices 0·5 mm thick and subsequently incubated for 12 h in a medium containing a [³⁵S]methionine–[³⁵S]cysteine mix and 0·8 mM-sodium laurate or oleate, the major fatty acids of CO and BT diets respectively. Concentrations of total [³⁵S]proteins, [³⁵S]albumin and [³⁵S]ApoB in liver cells were 2-fold lower (P=0·08, 0·0004 and 0·03 respectively) in CO- than in BT-fed calves. Although the total amount of proteins secreted (including albumin) was similar in both groups of calves, the amount of VLDL-[³⁵S]Apo secreted was 2-fold lower (P=0·004) in CO- than in BT-fed calves. These results suggest that a CO-enriched milk diet induces in preruminant calves a lipid infiltration of the liver by decreasing ApoB synthesis, leading to a reduction in secretion of VLDL particles.

Keywords:
Liver slices: Coconut oil: Apolipoprotein B: VLDL: Calf